blob: b80ea2f40344d5c065e86731041c07825650544e [file] [log] [blame]
"Robert P. J. Day"63fc1a92006-07-02 19:47:05 +00001/* vi: set sw=4 ts=4: */
Denys Vlasenko6b24d532010-03-22 13:42:13 +01002/*
Denys Vlasenko385b4562010-03-26 10:09:34 +01003 * udhcp client
Mike Frysinger7031f622006-05-08 03:20:50 +00004 * Russ Dill <Russ.Dill@asu.edu> July 2001
5 *
Denys Vlasenko6b24d532010-03-22 13:42:13 +01006 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Mike Frysinger7031f622006-05-08 03:20:50 +000019 */
Denys Vlasenkof7683cd2016-11-23 18:54:59 +010020//applet:IF_UDHCPC(APPLET(udhcpc, BB_DIR_SBIN, BB_SUID_DROP))
21
22//kbuild:lib-$(CONFIG_UDHCPC) += common.o packet.o signalpipe.o socket.o
23//kbuild:lib-$(CONFIG_UDHCPC) += dhcpc.o
24//kbuild:lib-$(CONFIG_FEATURE_UDHCPC_ARPING) += arpping.o
25//kbuild:lib-$(CONFIG_FEATURE_UDHCP_RFC3397) += domain_codec.o
26
Denis Vlasenkoaf1c8432007-03-26 13:22:35 +000027#include <syslog.h>
Denis Vlasenko1caca342007-08-02 10:14:29 +000028/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
29#define WANT_PIDFILE 1
Mike Frysinger7031f622006-05-08 03:20:50 +000030#include "common.h"
31#include "dhcpd.h"
32#include "dhcpc.h"
Denis Vlasenko5a3395b2006-11-18 19:51:32 +000033
Dan Fandrichf533ec82011-06-10 05:17:59 +020034#include <netinet/if_ether.h>
Denys Vlasenko6b24d532010-03-22 13:42:13 +010035#include <linux/filter.h>
Alexey Froloff3c62bba2012-09-17 16:02:44 +020036#include <linux/if_packet.h>
Denys Vlasenko6b24d532010-03-22 13:42:13 +010037
Denys Vlasenkof2bf20f2015-10-08 18:13:57 +020038#ifndef PACKET_AUXDATA
39# define PACKET_AUXDATA 8
40struct tpacket_auxdata {
41 uint32_t tp_status;
42 uint32_t tp_len;
43 uint32_t tp_snaplen;
44 uint16_t tp_mac;
45 uint16_t tp_net;
46 uint16_t tp_vlan_tci;
47 uint16_t tp_padding;
48};
49#endif
50
51
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +020052/* "struct client_data_t client_data" is in bb_common_bufsiz1 */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +000053
Mike Frysinger7031f622006-05-08 03:20:50 +000054
Keith Younge6bb8d32011-03-07 03:18:46 +010055#if ENABLE_LONG_OPTS
56static const char udhcpc_longopts[] ALIGN1 =
57 "clientid-none\0" No_argument "C"
Denys Vlasenko698cdef2021-06-02 15:07:46 +020058 "vendorclass\0" Required_argument "V" //deprecated
Keith Younge6bb8d32011-03-07 03:18:46 +010059 "fqdn\0" Required_argument "F"
60 "interface\0" Required_argument "i"
61 "now\0" No_argument "n"
62 "pidfile\0" Required_argument "p"
63 "quit\0" No_argument "q"
64 "release\0" No_argument "R"
65 "request\0" Required_argument "r"
66 "script\0" Required_argument "s"
67 "timeout\0" Required_argument "T"
Keith Younge6bb8d32011-03-07 03:18:46 +010068 "retries\0" Required_argument "t"
69 "tryagain\0" Required_argument "A"
70 "syslog\0" No_argument "S"
71 "request-option\0" Required_argument "O"
72 "no-default-options\0" No_argument "o"
73 "foreground\0" No_argument "f"
Denys Vlasenkoed820cc2017-05-08 15:11:02 +020074 USE_FOR_MMU(
Keith Younge6bb8d32011-03-07 03:18:46 +010075 "background\0" No_argument "b"
Denys Vlasenkoed820cc2017-05-08 15:11:02 +020076 )
Keith Younge6bb8d32011-03-07 03:18:46 +010077 "broadcast\0" No_argument "B"
Michel Stam9f412712014-10-30 11:59:04 +010078 IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
Keith Younge6bb8d32011-03-07 03:18:46 +010079 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
80 ;
81#endif
82/* Must match getopt32 option string order */
83enum {
84 OPT_C = 1 << 0,
85 OPT_V = 1 << 1,
Denys Vlasenko698cdef2021-06-02 15:07:46 +020086 OPT_F = 1 << 2,
87 OPT_i = 1 << 3,
88 OPT_n = 1 << 4,
89 OPT_p = 1 << 5,
90 OPT_q = 1 << 6,
91 OPT_R = 1 << 7,
92 OPT_r = 1 << 8,
93 OPT_s = 1 << 9,
94 OPT_T = 1 << 10,
95 OPT_t = 1 << 11,
96 OPT_S = 1 << 12,
97 OPT_A = 1 << 13,
98 OPT_O = 1 << 14,
99 OPT_o = 1 << 15,
100 OPT_x = 1 << 16,
101 OPT_f = 1 << 17,
102 OPT_B = 1 << 18,
Keith Younge6bb8d32011-03-07 03:18:46 +0100103/* The rest has variable bit positions, need to be clever */
Denys Vlasenko698cdef2021-06-02 15:07:46 +0200104 OPTBIT_B = 18,
Keith Younge6bb8d32011-03-07 03:18:46 +0100105 USE_FOR_MMU( OPTBIT_b,)
106 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
107 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
108 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
109 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
110 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
111};
112
113
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100114/*** Script execution code ***/
Martin Lewis9914d8b2020-08-04 17:27:16 -0500115struct dhcp_optitem {
116 unsigned len;
117 uint8_t code;
118 uint8_t malloced;
119 uint8_t *data;
120 char *env;
121};
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100122
123/* get a rough idea of how long an option will be (rounding up...) */
Denys Vlasenko3e134eb2016-04-22 18:09:21 +0200124static const uint8_t len_of_option_as_string[] ALIGN1 = {
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200125 [OPTION_IP ] = sizeof("255.255.255.255 "),
126 [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
127 [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
Denys Vlasenko352f79a2016-02-26 15:54:56 +0100128 [OPTION_6RD ] = sizeof("132 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "),
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200129 [OPTION_STRING ] = 1,
Denys Vlasenkod2266d42012-04-22 03:37:01 +0200130 [OPTION_STRING_HOST ] = 1,
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100131#if ENABLE_FEATURE_UDHCP_RFC3397
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200132 [OPTION_DNS_STRING ] = 1, /* unused */
133 /* Hmmm, this severely overestimates size if SIP_SERVERS option
134 * is in domain name form: N-byte option in binary form
135 * mallocs ~16*N bytes. But it is freed almost at once.
136 */
137 [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100138#endif
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200139// [OPTION_BOOLEAN ] = sizeof("yes "),
140 [OPTION_U8 ] = sizeof("255 "),
141 [OPTION_U16 ] = sizeof("65535 "),
142// [OPTION_S16 ] = sizeof("-32768 "),
143 [OPTION_U32 ] = sizeof("4294967295 "),
144 [OPTION_S32 ] = sizeof("-2147483684 "),
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100145};
146
147/* note: ip is a pointer to an IP in network order, possibly misaliged */
148static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
149{
150 return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
151}
152
153/* really simple implementation, just count the bits */
154static int mton(uint32_t mask)
155{
156 int i = 0;
157 mask = ntohl(mask); /* 111110000-like bit pattern */
158 while (mask) {
159 i++;
160 mask <<= 1;
161 }
162 return i;
163}
164
Denys Vlasenko85090c12014-06-16 00:17:00 +0200165#if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
Denys Vlasenko7280d202011-12-08 16:41:05 +0100166/* Check if a given name represents a valid DNS name */
167/* See RFC1035, 2.3.1 */
Martin Lewis726d0d12020-05-04 16:59:14 -0500168/* We don't need to be particularly anal. For example, allowing _, hyphen
169 * at the end, or leading and trailing dots would be ok, since it
170 * can't be used for attacks. (Leading hyphen can be, if someone uses cmd "$hostname"
171 * in the script: then hostname may be treated as an option)
172 */
Denys Vlasenko7280d202011-12-08 16:41:05 +0100173static int good_hostname(const char *name)
174{
Martin Lewis726d0d12020-05-04 16:59:14 -0500175 if (*name == '-') /* Can't start with '-' */
176 return 0;
Denys Vlasenko7280d202011-12-08 16:41:05 +0100177
Martin Lewis726d0d12020-05-04 16:59:14 -0500178 while (*name) {
179 unsigned char ch = *name++;
180 if (!isalnum(ch))
181 /* DNS allows only '-', but we are more permissive */
182 if (ch != '-' && ch != '_' && ch != '.')
183 return 0;
184 // TODO: do we want to validate lengths against NS_MAXLABEL and NS_MAXDNAME?
Denys Vlasenko7280d202011-12-08 16:41:05 +0100185 }
Martin Lewis726d0d12020-05-04 16:59:14 -0500186 return 1;
Denys Vlasenko7280d202011-12-08 16:41:05 +0100187}
Denys Vlasenko85090c12014-06-16 00:17:00 +0200188#else
189# define good_hostname(name) 1
190#endif
Denys Vlasenko7280d202011-12-08 16:41:05 +0100191
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100192/* Create "opt_name=opt_value" string */
Martin Lewis9914d8b2020-08-04 17:27:16 -0500193static NOINLINE char *xmalloc_optname_optval(const struct dhcp_optitem *opt_item, const struct dhcp_optflag *optflag, const char *opt_name)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100194{
195 unsigned upper_length;
196 int len, type, optlen;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100197 char *dest, *ret;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500198 uint8_t *option;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100199
Martin Lewis9914d8b2020-08-04 17:27:16 -0500200 option = opt_item->data;
201 len = opt_item->len;
Denys Vlasenkoc03602b2010-04-04 15:28:49 +0200202 type = optflag->flags & OPTION_TYPE_MASK;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100203 optlen = dhcp_option_lengths[type];
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200204 upper_length = len_of_option_as_string[type]
Denys Vlasenko352f79a2016-02-26 15:54:56 +0100205 * ((unsigned)(len + optlen) / (unsigned)optlen);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100206
207 dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
208 dest += sprintf(ret, "%s=", opt_name);
209
210 while (len >= optlen) {
211 switch (type) {
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200212 case OPTION_IP:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100213 case OPTION_IP_PAIR:
214 dest += sprint_nip(dest, "", option);
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500215 if (type == OPTION_IP_PAIR)
216 dest += sprint_nip(dest, "/", option + 4);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100217 break;
Denys Vlasenkoa8f6b992010-03-26 08:35:24 +0100218// case OPTION_BOOLEAN:
219// dest += sprintf(dest, *option ? "yes" : "no");
220// break;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100221 case OPTION_U8:
222 dest += sprintf(dest, "%u", *option);
223 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200224// case OPTION_S16:
225 case OPTION_U16: {
226 uint16_t val_u16;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100227 move_from_unaligned16(val_u16, option);
228 dest += sprintf(dest, "%u", ntohs(val_u16));
229 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200230 }
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100231 case OPTION_S32:
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200232 case OPTION_U32: {
233 uint32_t val_u32;
234 move_from_unaligned32(val_u32, option);
235 dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100236 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200237 }
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200238 /* Note: options which use 'return' instead of 'break'
239 * (for example, OPTION_STRING) skip the code which handles
240 * the case of list of options.
241 */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100242 case OPTION_STRING:
Denys Vlasenko7280d202011-12-08 16:41:05 +0100243 case OPTION_STRING_HOST:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100244 memcpy(dest, option, len);
245 dest[len] = '\0';
Denys Vlasenko02cf1492018-08-01 13:36:36 +0200246//TODO: it appears option 15 DHCP_DOMAIN_NAME is often abused
247//by DHCP admins to contain a space-separated list of domains,
248//not one domain name (presumably, to work as list of search domains,
249//instead of using proper option 119 DHCP_DOMAIN_SEARCH).
250//Currently, good_hostname() balks on strings containing spaces.
251//Do we need to allow it? Only for DHCP_DOMAIN_NAME option?
Denys Vlasenko7280d202011-12-08 16:41:05 +0100252 if (type == OPTION_STRING_HOST && !good_hostname(dest))
253 safe_strncpy(dest, "bad", len);
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200254 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100255 case OPTION_STATIC_ROUTES: {
256 /* Option binary format:
257 * mask [one byte, 0..32]
258 * ip [big endian, 0..4 bytes depending on mask]
259 * router [big endian, 4 bytes]
260 * may be repeated
261 *
262 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
263 */
264 const char *pfx = "";
265
266 while (len >= 1 + 4) { /* mask + 0-byte ip + router */
267 uint32_t nip;
268 uint8_t *p;
269 unsigned mask;
270 int bytes;
271
272 mask = *option++;
273 if (mask > 32)
274 break;
275 len--;
276
277 nip = 0;
278 p = (void*) &nip;
279 bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
280 while (--bytes >= 0) {
281 *p++ = *option++;
282 len--;
283 }
284 if (len < 4)
285 break;
286
287 /* print ip/mask */
288 dest += sprint_nip(dest, pfx, (void*) &nip);
289 pfx = " ";
290 dest += sprintf(dest, "/%u ", mask);
291 /* print router */
292 dest += sprint_nip(dest, "", option);
293 option += 4;
294 len -= 4;
295 }
296
297 return ret;
298 }
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200299 case OPTION_6RD:
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200300 /* Option binary format (see RFC 5969):
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200301 * 0 1 2 3
302 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200303 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
304 * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen |
305 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200306 * | 6rdPrefix |
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200307 * ... (16 octets) ...
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200308 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200309 * ... 6rdBRIPv4Address(es) ...
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200310 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200311 * We convert it to a string
312 * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200313 *
314 * Sanity check: ensure that our length is at least 22 bytes, that
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200315 * IPv4MaskLen <= 32,
316 * 6rdPrefixLen <= 128,
317 * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500318 * (2nd condition needs no check - it follows from 1st and 3rd).
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200319 * Else, return envvar with empty value ("optname=")
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200320 */
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200321 if (len >= (1 + 1 + 16 + 4)
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200322 && option[0] <= 32
323 && (option[1] + 32 - option[0]) <= 128
324 ) {
325 /* IPv4MaskLen */
326 dest += sprintf(dest, "%u ", *option++);
327 /* 6rdPrefixLen */
328 dest += sprintf(dest, "%u ", *option++);
329 /* 6rdPrefix */
Denys Vlasenko42816c22011-10-20 10:52:07 +0200330 dest += sprint_nip6(dest, /* "", */ option);
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200331 option += 16;
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500332 len -= 1 + 1 + 16;
333 *dest++ = ' ';
334 /* 6rdBRIPv4Address(es), use common IPv4 logic to process them */
335 type = OPTION_IP;
336 optlen = 4;
337 continue;
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200338 }
339
340 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100341#if ENABLE_FEATURE_UDHCP_RFC3397
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200342 case OPTION_DNS_STRING:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100343 /* unpack option into dest; use ret for prefix (i.e., "optname=") */
344 dest = dname_dec(option, len, ret);
345 if (dest) {
346 free(ret);
347 return dest;
348 }
349 /* error. return "optname=" string */
350 return ret;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200351 case OPTION_SIP_SERVERS:
352 /* Option binary format:
353 * type: byte
354 * type=0: domain names, dns-compressed
355 * type=1: IP addrs
356 */
357 option++;
358 len--;
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500359 if (option[-1] == 1) {
360 /* use common IPv4 logic to process IP addrs */
361 type = OPTION_IP;
362 optlen = 4;
363 continue;
364 }
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200365 if (option[-1] == 0) {
366 dest = dname_dec(option, len, ret);
367 if (dest) {
368 free(ret);
369 return dest;
370 }
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200371 }
372 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100373#endif
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200374 } /* switch */
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200375
376 /* If we are here, try to format any remaining data
377 * in the option as another, similarly-formatted option
378 */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100379 option += optlen;
380 len -= optlen;
Vladislav Grishenkoad8def22010-10-17 12:27:50 +0200381// TODO: it can be a list only if (optflag->flags & OPTION_LIST).
382// Should we bail out/warn if we see multi-ip option which is
383// not allowed to be such (for example, DHCP_BROADCAST)? -
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200384 if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100385 break;
386 *dest++ = ' ';
387 *dest = '\0';
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200388 } /* while */
389
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100390 return ret;
391}
392
Martin Lewis9914d8b2020-08-04 17:27:16 -0500393static void optitem_unset_env_and_free(void *item)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100394{
Martin Lewis9914d8b2020-08-04 17:27:16 -0500395 struct dhcp_optitem *opt_item = item;
396 bb_unsetenv_and_free(opt_item->env);
397 if (opt_item->malloced)
398 free(opt_item->data);
399 free(opt_item);
400}
401
402/* Used by static options (interface, siaddr, etc) */
403static void putenvp(char *new_opt)
404{
405 struct dhcp_optitem *opt_item;
406
407 opt_item = xzalloc(sizeof(*opt_item));
408 /* opt_item->code = 0, so it won't appear in concat_option's lookup */
409 /* opt_item->malloced = 0 */
410 /* opt_item->data = NULL */
411 opt_item->env = new_opt;
412 llist_add_to(&client_data.envp, opt_item);
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500413 log2(" %s", new_opt);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500414 putenv(new_opt);
415}
416
417/* Support RFC3396 Long Encoded Options */
418static struct dhcp_optitem *concat_option(uint8_t *data, uint8_t len, uint8_t code)
419{
420 llist_t *item;
421 struct dhcp_optitem *opt_item;
422
423 /* Check if an option with the code already exists.
424 * A possible optimization is to create a bitmap of all existing options in the packet,
425 * and iterate over the option list only if they exist.
426 * This will result in bigger code, and because dhcp packets don't have too many options it
427 * shouldn't have a big impact on performance.
428 */
429 for (item = client_data.envp; item != NULL; item = item->link) {
430 opt_item = (struct dhcp_optitem *)item->data;
431 if (opt_item->code == code) {
432 /* This option was seen already, concatenate */
433 uint8_t *new_data;
434
435 new_data = xmalloc(len + opt_item->len);
436 memcpy(
437 mempcpy(new_data, opt_item->data, opt_item->len),
438 data, len
439 );
440 opt_item->len += len;
441 if (opt_item->malloced)
442 free(opt_item->data);
443 opt_item->malloced = 1;
444 opt_item->data = new_data;
445 return opt_item;
446 }
447 }
448
449 /* This is a new option, add a new dhcp_optitem to the list */
450 opt_item = xzalloc(sizeof(*opt_item));
451 opt_item->code = code;
452 /* opt_item->malloced = 0 */
453 opt_item->data = data;
454 opt_item->len = len;
455 llist_add_to(&client_data.envp, opt_item);
456 return opt_item;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500457}
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100458
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500459static const char* get_optname(uint8_t code, const struct dhcp_optflag **dh)
460{
461 /* Find the option:
462 * dhcp_optflags is sorted so we stop searching when dh->code >= code, which is faster
463 * than iterating over the entire array.
464 * Options which don't have a match in dhcp_option_strings[], e.g DHCP_REQUESTED_IP,
465 * are located after the sorted array, so these entries will never be reached
466 * and they'll count as unknown options.
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200467 */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500468 for (*dh = dhcp_optflags; (*dh)->code && (*dh)->code < code; (*dh)++)
Martin Lewis9914d8b2020-08-04 17:27:16 -0500469 continue;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100470
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500471 if ((*dh)->code == code)
472 return nth_string(dhcp_option_strings, (*dh - dhcp_optflags));
473
474 return NULL;
475}
476
477/* put all the parameters into the environment */
Martin Lewis9914d8b2020-08-04 17:27:16 -0500478static void fill_envp(struct dhcp_packet *packet)
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500479{
480 uint8_t *optptr;
481 struct dhcp_scan_state scan_state;
482 char *new_opt;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500483
Martin Lewis9914d8b2020-08-04 17:27:16 -0500484 putenvp(xasprintf("interface=%s", client_data.interface));
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100485
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200486 if (!packet)
Martin Lewis9914d8b2020-08-04 17:27:16 -0500487 return;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100488
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500489 init_scan_state(packet, &scan_state);
490
491 /* Iterate over the packet options.
492 * Handle each option based on whether it's an unknown / known option.
Martin Lewis9914d8b2020-08-04 17:27:16 -0500493 * Long options are supported in compliance with RFC 3396.
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500494 */
495 while ((optptr = udhcp_scan_options(packet, &scan_state)) != NULL) {
496 const struct dhcp_optflag *dh;
497 const char *opt_name;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500498 struct dhcp_optitem *opt_item;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500499 uint8_t code = optptr[OPT_CODE];
500 uint8_t len = optptr[OPT_LEN];
501 uint8_t *data = optptr + OPT_DATA;
502
Martin Lewis9914d8b2020-08-04 17:27:16 -0500503 opt_item = concat_option(data, len, code);
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500504 opt_name = get_optname(code, &dh);
505 if (opt_name) {
Martin Lewis9914d8b2020-08-04 17:27:16 -0500506 new_opt = xmalloc_optname_optval(opt_item, dh, opt_name);
507 if (opt_item->code == DHCP_SUBNET && opt_item->len == 4) {
508 /* Generate extra envvar for DHCP_SUBNET, $mask */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500509 uint32_t subnet;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500510 move_from_unaligned32(subnet, opt_item->data);
511 putenvp(xasprintf("mask=%u", mton(subnet)));
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500512 }
513 } else {
514 unsigned ofs;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500515 new_opt = xmalloc(sizeof("optNNN=") + 1 + opt_item->len*2);
516 ofs = sprintf(new_opt, "opt%u=", opt_item->code);
517 bin2hex(new_opt + ofs, (char *)opt_item->data, opt_item->len)[0] = '\0';
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500518 }
Martin Lewis9914d8b2020-08-04 17:27:16 -0500519 log2(" %s", new_opt);
520 putenv(new_opt);
521 /* putenv will replace the existing environment variable in case of a duplicate.
522 * Free the previous occurrence (NULL if it's the first one).
523 */
524 free(opt_item->env);
525 opt_item->env = new_opt;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500526 }
527
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200528 /* Export BOOTP fields. Fields we don't (yet?) export:
529 * uint8_t op; // always BOOTREPLY
530 * uint8_t htype; // hardware address type. 1 = 10mb ethernet
531 * uint8_t hlen; // hardware address length
532 * uint8_t hops; // used by relay agents only
533 * uint32_t xid;
534 * uint16_t secs; // elapsed since client began acquisition/renewal
535 * uint16_t flags; // only one flag so far: bcast. Never set by server
536 * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
Brian Foleyf9beeb22016-10-25 14:20:55 +0200537 * // if during renew server wants to give us different IP?)
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200538 * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200539 */
540 /* Most important one: yiaddr as $ip */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500541 new_opt = xmalloc(sizeof("ip=255.255.255.255"));
542 sprint_nip(new_opt, "ip=", (uint8_t *) &packet->yiaddr);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500543 putenvp(new_opt);
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500544
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200545 if (packet->siaddr_nip) {
546 /* IP address of next server to use in bootstrap */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500547 new_opt = xmalloc(sizeof("siaddr=255.255.255.255"));
548 sprint_nip(new_opt, "siaddr=", (uint8_t *) &packet->siaddr_nip);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500549 putenvp(new_opt);
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200550 }
Martin Lewisd378fa12019-06-10 17:06:17 +0200551 if (packet->gateway_nip) {
Denys Vlasenko84d38502019-06-13 10:02:03 +0200552 /* IP address of DHCP relay agent */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500553 new_opt = xmalloc(sizeof("giaddr=255.255.255.255"));
554 sprint_nip(new_opt, "giaddr=", (uint8_t *) &packet->gateway_nip);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500555 putenvp(new_opt);
Martin Lewisd378fa12019-06-10 17:06:17 +0200556 }
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500557 if (!(scan_state.overload & FILE_FIELD) && packet->file[0]) {
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200558 /* watch out for invalid packets */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500559 new_opt = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500560 putenvp(new_opt);
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200561 }
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500562 if (!(scan_state.overload & SNAME_FIELD) && packet->sname[0]) {
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200563 /* watch out for invalid packets */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500564 new_opt = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500565 putenvp(new_opt);
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200566 }
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100567}
568
Denys Vlasenkof6def872021-06-03 16:14:04 +0200569/* Call a script with env vars */
570static void d4_run_script(struct dhcp_packet *packet, const char *name)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100571{
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100572 char *argv[3];
573
Martin Lewis9914d8b2020-08-04 17:27:16 -0500574 fill_envp(packet);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100575
576 /* call script */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200577 log1("executing %s %s", client_data.script, name);
578 argv[0] = (char*) client_data.script;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100579 argv[1] = (char*) name;
580 argv[2] = NULL;
581 spawn_and_wait(argv);
582
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500583 /* Free all allocated environment variables */
Martin Lewis9914d8b2020-08-04 17:27:16 -0500584 llist_free(client_data.envp, optitem_unset_env_and_free);
585 client_data.envp = NULL;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100586}
587
Denys Vlasenkof6def872021-06-03 16:14:04 +0200588static void d4_run_script_deconfig(void)
589{
590 d4_run_script(NULL, "deconfig");
591}
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100592
593/*** Sending/receiving packets ***/
594
Denys Vlasenko8d114452010-03-22 13:44:09 +0100595static ALWAYS_INLINE uint32_t random_xid(void)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100596{
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100597 return rand();
598}
599
600/* Initialize the packet with the proper defaults */
601static void init_packet(struct dhcp_packet *packet, char type)
602{
Denys Vlasenko11e024a2019-09-24 14:01:00 +0200603 unsigned secs;
Denys Vlasenko9ac55962011-03-12 05:37:54 +0100604
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200605 /* Fill in: op, htype, hlen, cookie fields; message type option: */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100606 udhcp_init_header(packet, type);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200607
608 packet->xid = random_xid();
609
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200610 client_data.last_secs = monotonic_sec();
611 if (client_data.first_secs == 0)
612 client_data.first_secs = client_data.last_secs;
613 secs = client_data.last_secs - client_data.first_secs;
Denys Vlasenko11e024a2019-09-24 14:01:00 +0200614 packet->secs = (secs < 0xffff) ? htons(secs) : 0xffff;
Denys Vlasenko9ac55962011-03-12 05:37:54 +0100615
Denys Vlasenko949e9622021-06-02 15:51:50 +0200616 memcpy(packet->chaddr, client_data.client_mac, 6);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100617}
618
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100619static void add_client_options(struct dhcp_packet *packet)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100620{
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200621 int i, end, len;
622
623 udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200624
Denys Vlasenko7724c762010-03-26 09:32:09 +0100625 /* Add a "param req" option with the list of options we'd like to have
Denys Vlasenkoa8f6b992010-03-26 08:35:24 +0100626 * from stubborn DHCP servers. Pull the data from the struct in common.c.
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100627 * No bounds checking because it goes towards the head of the packet. */
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200628 end = udhcp_end_option(packet->options);
629 len = 0;
Denys Vlasenko293c9452012-07-27 13:25:07 +0200630 for (i = 1; i < DHCP_END; i++) {
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200631 if (client_data.opt_mask[i >> 3] & (1 << (i & 7))) {
Denys Vlasenko293c9452012-07-27 13:25:07 +0200632 packet->options[end + OPT_DATA + len] = i;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100633 len++;
634 }
635 }
636 if (len) {
637 packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
638 packet->options[end + OPT_LEN] = len;
639 packet->options[end + OPT_DATA + len] = DHCP_END;
640 }
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100641
Keith Younge6bb8d32011-03-07 03:18:46 +0100642 /* Request broadcast replies if we have no IP addr */
643 if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
644 packet->flags |= htons(BROADCAST_FLAG);
645
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100646 /* Add -x options if any */
647 {
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200648 struct option_set *curr = client_data.options;
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100649 while (curr) {
Denys Vlasenko7724c762010-03-26 09:32:09 +0100650 udhcp_add_binary_option(packet, curr->data);
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100651 curr = curr->next;
652 }
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200653// if (client_data.sname)
654// strncpy((char*)packet->sname, client_data.sname, sizeof(packet->sname) - 1);
655// if (client_data.boot_file)
656// strncpy((char*)packet->file, client_data.boot_file, sizeof(packet->file) - 1);
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100657 }
Denys Vlasenko2017d482011-11-05 01:24:14 +0100658
659 // This will be needed if we remove -V VENDOR_STR in favor of
660 // -x vendor:VENDOR_STR
661 //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
662 // /* not set, set the default vendor ID */
663 // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100664}
665
Denys Vlasenko40a327a2021-06-15 00:34:04 +0200666static void add_serverid_and_clientid_options(struct dhcp_packet *packet, uint32_t server)
667{
668 struct option_set *ci;
669
670 udhcp_add_simple_option(packet, DHCP_SERVER_ID, server);
671
672 /* RFC 2131 section 2:
673 * If the client uses a 'client identifier' in one message,
674 * it MUST use that same identifier in all subsequent messages.
675 * section 3.1.6:
676 * If the client used a 'client identifier' when it obtained the lease,
677 * it MUST use the same 'client identifier' in the DHCPRELEASE message.
678 */
679 ci = udhcp_find_option(client_data.options, DHCP_CLIENT_ID);
680 if (ci)
681 udhcp_add_binary_option(packet, ci->data);
682}
683
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100684/* RFC 2131
685 * 4.4.4 Use of broadcast and unicast
686 *
687 * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
688 * messages, unless the client knows the address of a DHCP server.
689 * The client unicasts DHCPRELEASE messages to the server. Because
690 * the client is declining the use of the IP address supplied by the server,
691 * the client broadcasts DHCPDECLINE messages.
692 *
693 * When the DHCP client knows the address of a DHCP server, in either
694 * INIT or REBOOTING state, the client may use that address
695 * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
696 * The client may also use unicast to send DHCPINFORM messages
697 * to a known DHCP server. If the client receives no response to DHCP
698 * messages sent to the IP address of a known DHCP server, the DHCP
699 * client reverts to using the IP broadcast address.
700 */
701
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200702static int raw_bcast_from_client_data_ifindex(struct dhcp_packet *packet, uint32_t src_nip)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100703{
704 return udhcp_send_raw_packet(packet,
Hans Dedeckerabe8f752016-02-18 12:27:07 +0100705 /*src*/ src_nip, CLIENT_PORT,
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100706 /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200707 client_data.ifindex);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100708}
709
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100710static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
711{
Denys Vlasenko148788e2018-06-21 17:36:22 +0200712 if (server)
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100713 return udhcp_send_kernel_packet(packet,
714 ciaddr, CLIENT_PORT,
Michal Kaziorb8176992020-12-15 09:53:40 +0000715 server, SERVER_PORT,
716 client_data.interface);
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200717 return raw_bcast_from_client_data_ifindex(packet, ciaddr);
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100718}
719
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100720/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200721/* NOINLINE: limit stack usage in caller */
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200722static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100723{
724 struct dhcp_packet packet;
725
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200726 /* Fill in: op, htype, hlen, cookie, chaddr fields,
727 * random xid field (we override it below),
Denys Vlasenko265fcdd2021-06-02 13:50:26 +0200728 * message type option:
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200729 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100730 init_packet(&packet, DHCPDISCOVER);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200731
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100732 packet.xid = xid;
733 if (requested)
Denys Vlasenko7724c762010-03-26 09:32:09 +0100734 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200735
736 /* Add options: maxsize,
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200737 * "param req" option according to -O, options specified with -x
738 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100739 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100740
Denys Vlasenko64483322021-02-20 18:09:54 +0100741 bb_simple_info_msg("broadcasting discover");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200742 return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100743}
744
745/* Broadcast a DHCP request message */
746/* RFC 2131 3.1 paragraph 3:
747 * "The client _broadcasts_ a DHCPREQUEST message..."
748 */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200749/* NOINLINE: limit stack usage in caller */
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200750static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100751{
752 struct dhcp_packet packet;
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +0200753 struct in_addr temp_addr;
Denys Vlasenko64483322021-02-20 18:09:54 +0100754 char server_str[sizeof("255.255.255.255")];
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100755
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200756/*
757 * RFC 2131 4.3.2 DHCPREQUEST message
758 * ...
759 * If the DHCPREQUEST message contains a 'server identifier'
760 * option, the message is in response to a DHCPOFFER message.
761 * Otherwise, the message is a request to verify or extend an
762 * existing lease. If the client uses a 'client identifier'
763 * in a DHCPREQUEST message, it MUST use that same 'client identifier'
764 * in all subsequent messages. If the client included a list
765 * of requested parameters in a DHCPDISCOVER message, it MUST
766 * include that list in all subsequent messages.
767 */
768 /* Fill in: op, htype, hlen, cookie, chaddr fields,
769 * random xid field (we override it below),
Denys Vlasenko265fcdd2021-06-02 13:50:26 +0200770 * message type option:
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200771 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100772 init_packet(&packet, DHCPREQUEST);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200773
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100774 packet.xid = xid;
Denys Vlasenko7724c762010-03-26 09:32:09 +0100775 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200776
Denys Vlasenko7724c762010-03-26 09:32:09 +0100777 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200778
779 /* Add options: maxsize,
Denys Vlasenko40a327a2021-06-15 00:34:04 +0200780 * "param req" option according to -O, options specified with -x
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200781 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100782 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100783
Denys Vlasenko64483322021-02-20 18:09:54 +0100784 temp_addr.s_addr = server;
785 strcpy(server_str, inet_ntoa(temp_addr));
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +0200786 temp_addr.s_addr = requested;
Denys Vlasenko64483322021-02-20 18:09:54 +0100787 bb_info_msg("broadcasting select for %s, server %s",
788 inet_ntoa(temp_addr),
789 server_str
790 );
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200791 return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100792}
793
794/* Unicast or broadcast a DHCP renew message */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200795/* NOINLINE: limit stack usage in caller */
796static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100797{
798 struct dhcp_packet packet;
799
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200800/*
801 * RFC 2131 4.3.2 DHCPREQUEST message
802 * ...
803 * DHCPREQUEST generated during RENEWING state:
804 *
805 * 'server identifier' MUST NOT be filled in, 'requested IP address'
806 * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
807 * client's IP address. In this situation, the client is completely
808 * configured, and is trying to extend its lease. This message will
809 * be unicast, so no relay agents will be involved in its
810 * transmission. Because 'giaddr' is therefore not filled in, the
811 * DHCP server will trust the value in 'ciaddr', and use it when
812 * replying to the client.
813 */
814 /* Fill in: op, htype, hlen, cookie, chaddr fields,
815 * random xid field (we override it below),
Denys Vlasenko265fcdd2021-06-02 13:50:26 +0200816 * message type option:
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200817 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100818 init_packet(&packet, DHCPREQUEST);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200819
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100820 packet.xid = xid;
821 packet.ciaddr = ciaddr;
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200822
823 /* Add options: maxsize,
Denys Vlasenko40a327a2021-06-15 00:34:04 +0200824 * "param req" option according to -O, options specified with -x
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200825 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100826 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100827
Denys Vlasenko64483322021-02-20 18:09:54 +0100828 if (server) {
829 struct in_addr temp_addr;
830 temp_addr.s_addr = server;
831 bb_info_msg("sending renew to server %s", inet_ntoa(temp_addr));
832 } else {
833 bb_simple_info_msg("broadcasting renew");
834 }
835
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100836 return bcast_or_ucast(&packet, ciaddr, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100837}
838
839#if ENABLE_FEATURE_UDHCPC_ARPING
840/* Broadcast a DHCP decline message */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200841/* NOINLINE: limit stack usage in caller */
Denys Vlasenko860491c2011-11-18 02:09:13 +0100842static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100843{
844 struct dhcp_packet packet;
845
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200846 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
Denys Vlasenko265fcdd2021-06-02 13:50:26 +0200847 * message type option:
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200848 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100849 init_packet(&packet, DHCPDECLINE);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200850
Denys Vlasenko860491c2011-11-18 02:09:13 +0100851#if 0
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200852 /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
853 * but in case the server is buggy and wants DHCPDECLINE's xid
854 * to match the xid which started entire handshake,
855 * we use the same xid we used in initial DHCPDISCOVER:
856 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100857 packet.xid = xid;
Denys Vlasenko860491c2011-11-18 02:09:13 +0100858#endif
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200859 /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
Denys Vlasenko7724c762010-03-26 09:32:09 +0100860 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200861
Denys Vlasenko40a327a2021-06-15 00:34:04 +0200862 add_serverid_and_clientid_options(&packet, server);
Denys Vlasenko265fcdd2021-06-02 13:50:26 +0200863
Denys Vlasenko64483322021-02-20 18:09:54 +0100864 bb_simple_info_msg("broadcasting decline");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200865 return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100866}
867#endif
868
869/* Unicast a DHCP release message */
Denys Vlasenko9d05ad02018-11-03 23:34:03 +0100870static
871ALWAYS_INLINE /* one caller, help compiler to use this fact */
872int send_release(uint32_t server, uint32_t ciaddr)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100873{
874 struct dhcp_packet packet;
875
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200876 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
Denys Vlasenko265fcdd2021-06-02 13:50:26 +0200877 * message type option:
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200878 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100879 init_packet(&packet, DHCPRELEASE);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200880
881 /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100882 packet.ciaddr = ciaddr;
883
Denys Vlasenko40a327a2021-06-15 00:34:04 +0200884 add_serverid_and_clientid_options(&packet, server);
Denys Vlasenko265fcdd2021-06-02 13:50:26 +0200885
James Byrne253c4e72019-04-12 17:01:51 +0000886 bb_info_msg("sending %s", "release");
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100887 /* Note: normally we unicast here since "server" is not zero.
888 * However, there _are_ people who run "address-less" DHCP servers,
889 * and reportedly ISC dhcp client and Windows allow that.
890 */
891 return bcast_or_ucast(&packet, ciaddr, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100892}
893
894/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200895/* NOINLINE: limit stack usage in caller */
Denys Vlasenkof6def872021-06-03 16:14:04 +0200896static NOINLINE int d4_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100897{
898 int bytes;
899 struct ip_udp_dhcp_packet packet;
900 uint16_t check;
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200901 unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
902 struct iovec iov;
903 struct msghdr msg;
904 struct cmsghdr *cmsg;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100905
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200906 /* used to use just safe_read(fd, &packet, sizeof(packet))
907 * but we need to check for TP_STATUS_CSUMNOTREADY :(
908 */
909 iov.iov_base = &packet;
910 iov.iov_len = sizeof(packet);
911 memset(&msg, 0, sizeof(msg));
912 msg.msg_iov = &iov;
913 msg.msg_iovlen = 1;
914 msg.msg_control = cmsgbuf;
915 msg.msg_controllen = sizeof(cmsgbuf);
916 for (;;) {
917 bytes = recvmsg(fd, &msg, 0);
918 if (bytes < 0) {
919 if (errno == EINTR)
920 continue;
James Byrne69374872019-07-02 11:35:03 +0200921 log1s("packet read error, ignoring");
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200922 /* NB: possible down interface, etc. Caller should pause. */
923 return bytes; /* returns -1 */
924 }
925 break;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100926 }
927
928 if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
James Byrne69374872019-07-02 11:35:03 +0200929 log1s("packet is too short, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100930 return -2;
931 }
932
933 if (bytes < ntohs(packet.ip.tot_len)) {
934 /* packet is bigger than sizeof(packet), we did partial read */
James Byrne69374872019-07-02 11:35:03 +0200935 log1s("oversized packet, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100936 return -2;
937 }
938
939 /* ignore any extra garbage bytes */
940 bytes = ntohs(packet.ip.tot_len);
941
942 /* make sure its the right packet for us, and that it passes sanity checks */
Denys Vlasenko7981d792011-10-20 10:34:05 +0200943 if (packet.ip.protocol != IPPROTO_UDP
944 || packet.ip.version != IPVERSION
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100945 || packet.ip.ihl != (sizeof(packet.ip) >> 2)
946 || packet.udp.dest != htons(CLIENT_PORT)
947 /* || bytes > (int) sizeof(packet) - can't happen */
948 || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
949 ) {
James Byrne69374872019-07-02 11:35:03 +0200950 log1s("unrelated/bogus packet, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100951 return -2;
952 }
953
954 /* verify IP checksum */
955 check = packet.ip.check;
956 packet.ip.check = 0;
Denys Vlasenko4a0eb032020-10-01 03:07:22 +0200957 if (check != inet_cksum(&packet.ip, sizeof(packet.ip))) {
James Byrne69374872019-07-02 11:35:03 +0200958 log1s("bad IP header checksum, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100959 return -2;
960 }
961
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200962 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
963 if (cmsg->cmsg_level == SOL_PACKET
964 && cmsg->cmsg_type == PACKET_AUXDATA
965 ) {
966 /* some VMs don't checksum UDP and TCP data
967 * they send to the same physical machine,
968 * here we detect this case:
969 */
970 struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
971 if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
972 goto skip_udp_sum_check;
973 }
974 }
975
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100976 /* verify UDP checksum. IP header has to be modified for this */
977 memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
978 /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
979 packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
980 check = packet.udp.check;
981 packet.udp.check = 0;
Denys Vlasenko4a0eb032020-10-01 03:07:22 +0200982 if (check && check != inet_cksum(&packet, bytes)) {
James Byrne69374872019-07-02 11:35:03 +0200983 log1s("packet with bad UDP checksum received, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100984 return -2;
985 }
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200986 skip_udp_sum_check:
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100987
Denys Vlasenko7981d792011-10-20 10:34:05 +0200988 if (packet.data.cookie != htonl(DHCP_MAGIC)) {
Denys Vlasenko4bbc3912021-06-02 19:51:52 +0200989 log1s("packet with bad magic, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100990 return -2;
991 }
Denys Vlasenko7981d792011-10-20 10:34:05 +0200992
Denys Vlasenko4bbc3912021-06-02 19:51:52 +0200993 log2("received %s", "a packet");
994 /* log2 because more informative msg for valid packets is printed later at log1 level */
Denys Vlasenko7981d792011-10-20 10:34:05 +0200995 udhcp_dump_packet(&packet.data);
996
997 bytes -= sizeof(packet.ip) + sizeof(packet.udp);
998 memcpy(dhcp_pkt, &packet.data, bytes);
999 return bytes;
Denys Vlasenko501e35c2010-03-22 13:43:12 +01001000}
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001001
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001002
1003/*** Main ***/
1004
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001005/* Values for client_data.listen_mode */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001006#define LISTEN_NONE 0
1007#define LISTEN_KERNEL 1
1008#define LISTEN_RAW 2
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001009
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001010/* Values for client_data.state */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001011/* initial state: (re)start DHCP negotiation */
1012#define INIT_SELECTING 0
1013/* discover was sent, DHCPOFFER reply received */
1014#define REQUESTING 1
1015/* select/renew was sent, DHCPACK reply received */
1016#define BOUND 2
1017/* half of lease passed, want to renew it by sending unicast renew requests */
1018#define RENEWING 3
1019/* renew requests were not answered, lease is almost over, send broadcast renew */
1020#define REBINDING 4
1021/* manually requested renew (SIGUSR1) */
1022#define RENEW_REQUESTED 5
1023/* release, possibly manually requested (SIGUSR2) */
1024#define RELEASED 6
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001025
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001026static int udhcp_raw_socket(int ifindex)
1027{
1028 int fd;
1029 struct sockaddr_ll sock;
1030
Denys Vlasenko168f0ef2017-07-21 12:04:22 +02001031 log2("opening raw socket on ifindex %d", ifindex);
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001032
1033 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
Denys Vlasenko744ee5d2014-02-07 17:38:52 +01001034 /* ^^^^^
1035 * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
1036 * ETH_P_IP: want to receive only packets with IPv4 eth type
1037 */
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001038
Denys Vlasenko2b9acc62017-09-29 14:09:02 +02001039 memset(&sock, 0, sizeof(sock)); /* let's be deterministic */
Vladislav Grishenko713e6d72011-02-14 04:50:30 +01001040 sock.sll_family = AF_PACKET;
1041 sock.sll_protocol = htons(ETH_P_IP);
1042 sock.sll_ifindex = ifindex;
Denys Vlasenko2b9acc62017-09-29 14:09:02 +02001043 /*sock.sll_hatype = ARPHRD_???;*/
1044 /*sock.sll_pkttype = PACKET_???;*/
1045 /*sock.sll_halen = ???;*/
1046 /*sock.sll_addr[8] = ???;*/
Vladislav Grishenko713e6d72011-02-14 04:50:30 +01001047 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
1048
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001049#if 0 /* Several users reported breakage when BPF filter is used */
Vladislav Grishenko713e6d72011-02-14 04:50:30 +01001050 if (CLIENT_PORT == 68) {
1051 /* Use only if standard port is in use */
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001052 /*
1053 * I've selected not to see LL header, so BPF doesn't see it, too.
1054 * The filter may also pass non-IP and non-ARP packets, but we do
1055 * a more complete check when receiving the message in userspace.
1056 *
1057 * and filter shamelessly stolen from:
1058 *
1059 * http://www.flamewarmaster.de/software/dhcpclient/
1060 *
1061 * There are a few other interesting ideas on that page (look under
1062 * "Motivation"). Use of netlink events is most interesting. Think
1063 * of various network servers listening for events and reconfiguring.
1064 * That would obsolete sending HUP signals and/or make use of restarts.
1065 *
1066 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
1067 * License: GPL v2.
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001068 */
1069 static const struct sock_filter filter_instr[] = {
1070 /* load 9th byte (protocol) */
1071 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
1072 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
1073 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
1074 /* L1: load halfword from offset 6 (flags and frag offset) */
1075 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
1076 /* jump to L4 if any bits in frag offset field are set, else to L2 */
1077 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
1078 /* L2: skip IP header (load index reg with header len) */
1079 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
1080 /* load udp destination port from halfword[header_len + 2] */
1081 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
1082 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
1083 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
Denys Vlasenkoffc3a932014-02-19 14:17:11 +01001084 /* L3: accept packet ("accept 0x7fffffff bytes") */
1085 /* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
1086 BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
1087 /* L4: discard packet ("accept zero bytes") */
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001088 BPF_STMT(BPF_RET|BPF_K, 0),
1089 };
1090 static const struct sock_fprog filter_prog = {
1091 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
1092 /* casting const away: */
1093 .filter = (struct sock_filter *) filter_instr,
1094 };
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001095 /* Ignoring error (kernel may lack support for this) */
1096 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
1097 sizeof(filter_prog)) >= 0)
Denys Vlasenko8f2e99c2016-03-30 18:41:23 +02001098 log1("attached filter to raw socket fd"); // log?
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001099 }
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001100#endif
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001101
Denys Vlasenkoc52cbea2015-08-24 19:48:03 +02001102 if (setsockopt_1(fd, SOL_PACKET, PACKET_AUXDATA) != 0) {
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001103 if (errno != ENOPROTOOPT)
James Byrne69374872019-07-02 11:35:03 +02001104 log1s("can't set PACKET_AUXDATA on raw socket");
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001105 }
1106
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001107 return fd;
1108}
1109
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001110static void change_listen_mode(int new_mode)
Mike Frysinger7031f622006-05-08 03:20:50 +00001111{
Denys Vlasenko8f2e99c2016-03-30 18:41:23 +02001112 log1("entering listen mode: %s",
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001113 new_mode != LISTEN_NONE
1114 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
1115 : "none"
1116 );
Denis Vlasenko517413f2008-12-10 11:16:47 +00001117
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001118 client_data.listen_mode = new_mode;
1119 if (client_data.sockfd >= 0) {
1120 close(client_data.sockfd);
1121 client_data.sockfd = -1;
Denis Vlasenkofbd29182007-04-07 01:05:47 +00001122 }
Denis Vlasenko517413f2008-12-10 11:16:47 +00001123 if (new_mode == LISTEN_KERNEL)
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001124 client_data.sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_data.interface);
Denis Vlasenko517413f2008-12-10 11:16:47 +00001125 else if (new_mode != LISTEN_NONE)
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001126 client_data.sockfd = udhcp_raw_socket(client_data.ifindex);
1127 /* else LISTEN_NONE: client_data.sockfd stays closed */
Mike Frysinger7031f622006-05-08 03:20:50 +00001128}
1129
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001130static void perform_release(uint32_t server_addr, uint32_t requested_ip)
Mike Frysinger7031f622006-05-08 03:20:50 +00001131{
Denis Vlasenko42b3dea2007-07-03 15:47:50 +00001132 char buffer[sizeof("255.255.255.255")];
Mike Frysinger7031f622006-05-08 03:20:50 +00001133 struct in_addr temp_addr;
1134
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001135 change_listen_mode(LISTEN_NONE);
1136
Mike Frysinger7031f622006-05-08 03:20:50 +00001137 /* send release packet */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001138 if (client_data.state == BOUND
1139 || client_data.state == RENEWING
1140 || client_data.state == REBINDING
1141 || client_data.state == RENEW_REQUESTED
Denys Vlasenko44399e02016-07-03 20:26:44 +02001142 ) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001143 temp_addr.s_addr = server_addr;
Denis Vlasenko42b3dea2007-07-03 15:47:50 +00001144 strcpy(buffer, inet_ntoa(temp_addr));
Mike Frysinger7031f622006-05-08 03:20:50 +00001145 temp_addr.s_addr = requested_ip;
James Byrne253c4e72019-04-12 17:01:51 +00001146 bb_info_msg("unicasting a release of %s to %s",
Mike Frysinger7031f622006-05-08 03:20:50 +00001147 inet_ntoa(temp_addr), buffer);
1148 send_release(server_addr, requested_ip); /* unicast */
Mike Frysinger7031f622006-05-08 03:20:50 +00001149 }
James Byrne69374872019-07-02 11:35:03 +02001150 bb_simple_info_msg("entering released state");
Peter Korsgaardb6355e22016-08-26 18:46:34 +02001151/*
1152 * We can be here on: SIGUSR2,
1153 * or on exit (SIGTERM) and -R "release on quit" is specified.
1154 * Users requested to be notified in all cases, even if not in one
1155 * of the states above.
1156 */
Denys Vlasenkof6def872021-06-03 16:14:04 +02001157 d4_run_script_deconfig();
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001158 client_data.state = RELEASED;
Mike Frysinger7031f622006-05-08 03:20:50 +00001159}
1160
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001161#if BB_MMU
1162static void client_background(void)
1163{
1164 bb_daemonize(0);
1165 logmode &= ~LOGMODE_STDIO;
1166 /* rewrite pidfile, as our pid is different now */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001167 write_pidfile(client_data.pidfile);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001168}
1169#endif
1170
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001171//usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1172//usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
1173//usage:#else
1174//usage:# define IF_UDHCP_VERBOSE(...)
1175//usage:#endif
1176//usage:#define udhcpc_trivial_usage
Michel Stam9f412712014-10-30 11:59:04 +01001177//usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001178//usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
1179//usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001180//usage:#define udhcpc_full_usage "\n"
Andre Kalb5f2e00f2020-05-05 18:24:25 +02001181//usage: "\n -i IFACE Interface to use (default "CONFIG_UDHCPC_DEFAULT_INTERFACE")"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001182//usage: IF_FEATURE_UDHCP_PORT(
1183//usage: "\n -P PORT Use PORT (default 68)"
1184//usage: )
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001185//usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001186//usage: "\n -p FILE Create pidfile"
Keith Younge6bb8d32011-03-07 03:18:46 +01001187//usage: "\n -B Request broadcast replies"
Denys Vlasenkoaadb4852013-08-05 02:21:36 +02001188//usage: "\n -t N Send up to N discover packets (default 3)"
Denys Vlasenko456687f2013-08-08 12:33:18 +02001189//usage: "\n -T SEC Pause between packets (default 3)"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001190//usage: "\n -A SEC Wait if lease is not obtained (default 20)"
Denys Vlasenko544143d2019-02-27 08:17:07 +01001191//usage: USE_FOR_MMU(
1192//usage: "\n -b Background if lease is not obtained"
1193//usage: )
Denys Vlasenko456687f2013-08-08 12:33:18 +02001194//usage: "\n -n Exit if lease is not obtained"
1195//usage: "\n -q Exit after obtaining lease"
1196//usage: "\n -R Release IP on exit"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001197//usage: "\n -f Run in foreground"
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001198//usage: "\n -S Log to syslog too"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001199//usage: IF_FEATURE_UDHCPC_ARPING(
Michel Stam9f412712014-10-30 11:59:04 +01001200//usage: "\n -a[MSEC] Validate offered address with ARP ping"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001201//usage: )
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001202//usage: "\n -r IP Request this IP address"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001203//usage: "\n -o Don't request any options (unless -O is given)"
1204//usage: "\n -O OPT Request option OPT from server (cumulative)"
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001205//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1206//usage: "\n Examples of string, numeric, and hex byte opts:"
1207//usage: "\n -x hostname:bbox - option 12"
1208//usage: "\n -x lease:3600 - option 51 (lease time)"
1209//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
Denys Vlasenko266f6f12018-04-13 13:18:34 +02001210//usage: "\n -x 14:'\"dumpfile\"' - option 14 (shell-quoted)"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001211//usage: "\n -F NAME Ask server to update DNS mapping for NAME"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001212//usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001213//usage: "\n -C Don't send MAC as client identifier"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001214//usage: IF_UDHCP_VERBOSE(
1215//usage: "\n -v Verbose"
1216//usage: )
Denys Vlasenko8993c3f2010-12-25 06:21:54 +01001217//usage: "\nSignals:"
Denys Vlasenko50089fc2011-11-07 15:44:46 +01001218//usage: "\n USR1 Renew lease"
1219//usage: "\n USR2 Release lease"
Denys Vlasenko8993c3f2010-12-25 06:21:54 +01001220
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +00001221int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +00001222int udhcpc_main(int argc UNUSED_PARAM, char **argv)
Mike Frysinger7031f622006-05-08 03:20:50 +00001223{
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001224 uint8_t *message;
Denys Vlasenko698cdef2021-06-02 15:07:46 +02001225 const char *str_V, *str_F, *str_r;
Michel Stam9f412712014-10-30 11:59:04 +01001226 IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001227 IF_FEATURE_UDHCP_PORT(char *str_P;)
Denys Vlasenko265fcdd2021-06-02 13:50:26 +02001228 uint8_t *clientid_mac_ptr;
Denis Vlasenko19183682007-12-10 07:03:38 +00001229 llist_t *list_O = NULL;
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001230 llist_t *list_x = NULL;
Denis Vlasenko68af8e72007-11-22 21:41:14 +00001231 int tryagain_timeout = 20;
1232 int discover_timeout = 3;
1233 int discover_retries = 3;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001234 uint32_t server_addr = server_addr; /* for compiler */
1235 uint32_t requested_ip = 0;
Denys Vlasenko860491c2011-11-18 02:09:13 +01001236 uint32_t xid = xid; /* for compiler */
Denis Vlasenkob539c842007-11-29 08:17:45 +00001237 int packet_num;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001238 int timeout; /* must be signed */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001239 int lease_remaining; /* must be signed */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001240 unsigned opt;
Michel Stam9f412712014-10-30 11:59:04 +01001241 IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001242 int retval;
Mike Frysinger7031f622006-05-08 03:20:50 +00001243
Denys Vlasenkodf70a432016-04-21 18:54:36 +02001244 setup_common_bufsiz();
1245
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001246 /* Default options */
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001247 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
1248 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
Andre Kalb5f2e00f2020-05-05 18:24:25 +02001249 client_data.interface = CONFIG_UDHCPC_DEFAULT_INTERFACE;
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001250 client_data.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
1251 client_data.sockfd = -1;
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001252 str_V = "udhcp "BB_VER;
Mike Frysinger7031f622006-05-08 03:20:50 +00001253
Denys Vlasenko65c34c52019-05-31 23:39:22 +02001254 /* Make sure fd 0,1,2 are open */
1255 /* Set up the signal pipe on fds 3,4 - must be before openlog() */
1256 udhcp_sp_setup();
1257
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001258 /* Parse command line */
Denys Vlasenko22542ec2017-08-08 21:55:02 +02001259 opt = getopt32long(argv, "^"
1260 /* O,x: list; -T,-t,-A take numeric param */
Denys Vlasenko698cdef2021-06-02 15:07:46 +02001261 "CV:F:i:np:qRr:s:T:+t:+SA:+O:*ox:*fB"
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001262 USE_FOR_MMU("b")
Michel Stam9f412712014-10-30 11:59:04 +01001263 IF_FEATURE_UDHCPC_ARPING("a::")
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001264 IF_FEATURE_UDHCP_PORT("P:")
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001265 "v"
Denys Vlasenko22542ec2017-08-08 21:55:02 +02001266 "\0" IF_UDHCP_VERBOSE("vv") /* -v is a counter */
Denys Vlasenko036585a2017-08-08 16:38:18 +02001267 , udhcpc_longopts
Denys Vlasenko698cdef2021-06-02 15:07:46 +02001268 , &str_V, &str_F
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001269 , &client_data.interface, &client_data.pidfile /* i,p */
Denys Vlasenko22542ec2017-08-08 21:55:02 +02001270 , &str_r /* r */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001271 , &client_data.script /* s */
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001272 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
Denis Vlasenko19183682007-12-10 07:03:38 +00001273 , &list_O
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001274 , &list_x
Michel Stam9f412712014-10-30 11:59:04 +01001275 IF_FEATURE_UDHCPC_ARPING(, &str_a)
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001276 IF_FEATURE_UDHCP_PORT(, &str_P)
Leonid Lisovskiy6c9c0a12011-10-18 00:35:47 +02001277 IF_UDHCP_VERBOSE(, &dhcp_verbose)
Denys Vlasenko7e21f042011-11-08 11:39:41 +01001278 );
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001279 if (opt & OPT_F) {
Denys Vlasenko949e9622021-06-02 15:51:50 +02001280 char *p;
1281 unsigned len;
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001282 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
Denys Vlasenko949e9622021-06-02 15:51:50 +02001283 len = strlen(str_F);
1284 p = udhcp_insert_new_option(
1285 &client_data.options, DHCP_FQDN,
1286 len + 3, /*dhcp6:*/ 0);
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001287 /* Flag bits: 0000NEOS
1288 * S: 1 = Client requests server to update A RR in DNS as well as PTR
1289 * O: 1 = Server indicates to client that DNS has been updated regardless
1290 * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
1291 * not "host.domain.com". Format 0 is obsolete.
1292 * N: 1 = Client requests server to not update DNS (S must be 0 then)
1293 * Two [0] bytes which follow are deprecated and must be 0.
1294 */
Denys Vlasenko949e9622021-06-02 15:51:50 +02001295 p[OPT_DATA + 0] = 0x1;
1296 /*p[OPT_DATA + 1] = 0; - xzalloc did it */
1297 /*p[OPT_DATA + 2] = 0; */
1298 memcpy(p + OPT_DATA + 3, str_F, len); /* do not store NUL byte */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001299 }
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001300 if (opt & OPT_r)
1301 requested_ip = inet_addr(str_r);
Denis Vlasenkod55fe3e2008-02-04 13:12:16 +00001302#if ENABLE_FEATURE_UDHCP_PORT
1303 if (opt & OPT_P) {
1304 CLIENT_PORT = xatou16(str_P);
1305 SERVER_PORT = CLIENT_PORT - 1;
1306 }
1307#endif
Michel Stam9f412712014-10-30 11:59:04 +01001308 IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
Denis Vlasenko19183682007-12-10 07:03:38 +00001309 while (list_O) {
Denis Vlasenko18c93022008-08-27 22:29:43 +00001310 char *optstr = llist_pop(&list_O);
Denys Vlasenko5d3aace2011-06-04 05:07:16 +02001311 unsigned n = bb_strtou(optstr, NULL, 0);
1312 if (errno || n > 254) {
Denys Vlasenkoba4fbca2017-06-28 19:18:17 +02001313 n = udhcp_option_idx(optstr, dhcp_option_strings);
Denys Vlasenko5d3aace2011-06-04 05:07:16 +02001314 n = dhcp_optflags[n].code;
1315 }
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001316 client_data.opt_mask[n >> 3] |= 1 << (n & 7);
Denis Vlasenko19183682007-12-10 07:03:38 +00001317 }
Denys Vlasenko293c9452012-07-27 13:25:07 +02001318 if (!(opt & OPT_o)) {
1319 unsigned i, n;
1320 for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
1321 if (dhcp_optflags[i].flags & OPTION_REQ) {
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001322 client_data.opt_mask[n >> 3] |= 1 << (n & 7);
Denys Vlasenko293c9452012-07-27 13:25:07 +02001323 }
1324 }
1325 }
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001326 while (list_x) {
Denys Vlasenko266f6f12018-04-13 13:18:34 +02001327 char *optstr = xstrdup(llist_pop(&list_x));
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001328 udhcp_str2optset(optstr, &client_data.options,
Denys Vlasenko60275972018-05-14 11:06:35 +02001329 dhcp_optflags, dhcp_option_strings,
1330 /*dhcpv6:*/ 0
1331 );
Denys Vlasenko266f6f12018-04-13 13:18:34 +02001332 free(optstr);
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001333 }
Denys Vlasenko698cdef2021-06-02 15:07:46 +02001334 if (str_V[0] != '\0') {
Denys Vlasenko949e9622021-06-02 15:51:50 +02001335 char *p;
Denys Vlasenko274ce6c2021-06-05 16:48:06 +02001336 unsigned len = strnlen(str_V, 254);
Denys Vlasenko949e9622021-06-02 15:51:50 +02001337 p = udhcp_insert_new_option(
Denys Vlasenko698cdef2021-06-02 15:07:46 +02001338 &client_data.options, DHCP_VENDOR,
Denys Vlasenko949e9622021-06-02 15:51:50 +02001339 len, /*dhcp6:*/ 0);
1340 memcpy(p + OPT_DATA, str_V, len); /* do not store NUL byte */
1341 }
1342
1343 clientid_mac_ptr = NULL;
1344 if (!(opt & OPT_C) && !udhcp_find_option(client_data.options, DHCP_CLIENT_ID)) {
1345 /* not suppressed and not set, create default client ID */
1346 clientid_mac_ptr = udhcp_insert_new_option(
1347 &client_data.options, DHCP_CLIENT_ID,
1348 1 + 6, /*dhcp6:*/ 0);
1349 clientid_mac_ptr[OPT_DATA] = 1; /* type: ethernet */
1350 clientid_mac_ptr += OPT_DATA + 1; /* skip option code, len, ethernet */
Denys Vlasenko698cdef2021-06-02 15:07:46 +02001351 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001352
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001353 /* Not really necessary (we redo it on every iteration)
1354 * but allows early (before daemonization) detection
1355 * of bad interface name.
1356 */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001357 if (udhcp_read_interface(client_data.interface,
1358 &client_data.ifindex,
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001359 NULL,
Denys Vlasenko949e9622021-06-02 15:51:50 +02001360 client_data.client_mac)
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001361 ) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001362 return 1;
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001363 }
1364
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001365#if !BB_MMU
1366 /* on NOMMU reexec (i.e., background) early */
1367 if (!(opt & OPT_f)) {
1368 bb_daemonize_or_rexec(0 /* flags */, argv);
Denis Vlasenkoa19e6492009-03-11 14:40:00 +00001369 logmode = LOGMODE_NONE;
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001370 }
1371#endif
1372 if (opt & OPT_S) {
Denis Vlasenko5e4fda02009-03-08 23:46:48 +00001373 openlog(applet_name, LOG_PID, LOG_DAEMON);
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001374 logmode |= LOGMODE_SYSLOG;
1375 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001376
Denis Vlasenko80edead2007-08-02 22:31:05 +00001377 /* Create pidfile */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001378 write_pidfile(client_data.pidfile);
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001379 /* Goes to stdout (unless NOMMU) and possibly syslog */
James Byrne69374872019-07-02 11:35:03 +02001380 bb_simple_info_msg("started, v"BB_VER);
Denys Vlasenko8d114452010-03-22 13:44:09 +01001381 /* We want random_xid to be random... */
1382 srand(monotonic_us());
Mike Frysinger7031f622006-05-08 03:20:50 +00001383
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001384 client_data.state = INIT_SELECTING;
Denys Vlasenkof6def872021-06-03 16:14:04 +02001385 d4_run_script_deconfig();
Denis Vlasenkob539c842007-11-29 08:17:45 +00001386 packet_num = 0;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001387 timeout = 0;
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001388 lease_remaining = 0;
Mike Frysinger7031f622006-05-08 03:20:50 +00001389
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001390 /* Main event loop. select() waits on signal pipe and possibly
1391 * on sockfd.
1392 * "continue" statements in code below jump to the top of the loop.
1393 */
Mike Frysinger7031f622006-05-08 03:20:50 +00001394 for (;;) {
Denys Vlasenko52a515d2017-02-16 23:25:44 +01001395 struct pollfd pfds[2];
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001396 struct dhcp_packet packet;
Mike Frysinger7031f622006-05-08 03:20:50 +00001397
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001398 //bb_error_msg("sockfd:%d, listen_mode:%d", client_data.sockfd, client_data.listen_mode);
Denis Vlasenko517413f2008-12-10 11:16:47 +00001399
1400 /* Was opening raw or udp socket here
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001401 * if (client_data.listen_mode != LISTEN_NONE && client_data.sockfd < 0),
Denis Vlasenko517413f2008-12-10 11:16:47 +00001402 * but on fast network renew responses return faster
1403 * than we open sockets. Thus this code is moved
1404 * to change_listen_mode(). Thus we open listen socket
1405 * BEFORE we send renew request (see "case BOUND:"). */
1406
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001407 udhcp_sp_fd_set(pfds, client_data.sockfd);
Mike Frysinger7031f622006-05-08 03:20:50 +00001408
Denys Vlasenko8d114452010-03-22 13:44:09 +01001409 retval = 0;
1410 /* If we already timed out, fall through with retval = 0, else... */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001411 if (timeout > 0) {
1412 unsigned diff;
1413
1414 if (timeout > INT_MAX/1000)
1415 timeout = INT_MAX/1000;
1416 log1("waiting %u seconds", timeout);
1417 diff = (unsigned)monotonic_sec();
1418 retval = poll(pfds, 2, timeout * 1000);
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001419 diff = (unsigned)monotonic_sec() - diff;
1420 lease_remaining -= diff;
1421 if (lease_remaining < 0)
1422 lease_remaining = 0;
1423 timeout -= diff;
1424 if (timeout < 0)
1425 timeout = 0;
1426
Denis Vlasenkob2342912008-05-21 07:02:16 +00001427 if (retval < 0) {
1428 /* EINTR? A signal was caught, don't panic */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001429 if (errno == EINTR) {
Denis Vlasenkob2342912008-05-21 07:02:16 +00001430 continue;
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001431 }
Denys Vlasenko10ad6222017-04-17 16:13:32 +02001432 /* Else: an error occurred, panic! */
James Byrne69374872019-07-02 11:35:03 +02001433 bb_simple_perror_msg_and_die("poll");
Denis Vlasenko80edead2007-08-02 22:31:05 +00001434 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001435 }
1436
1437 /* If timeout dropped to zero, time to become active:
1438 * resend discover/renew/whatever
1439 */
1440 if (retval == 0) {
Denys Vlasenkoa5048fa2010-10-20 21:38:29 +02001441 /* When running on a bridge, the ifindex may have changed
1442 * (e.g. if member interfaces were added/removed
1443 * or if the status of the bridge changed).
1444 * Refresh ifindex and client_mac:
1445 */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001446 if (udhcp_read_interface(client_data.interface,
1447 &client_data.ifindex,
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001448 NULL,
Denys Vlasenko949e9622021-06-02 15:51:50 +02001449 client_data.client_mac)
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001450 ) {
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001451 goto ret0; /* iface is gone? */
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001452 }
1453 if (clientid_mac_ptr)
Denys Vlasenko949e9622021-06-02 15:51:50 +02001454 memcpy(clientid_mac_ptr, client_data.client_mac, 6);
Denys Vlasenkoa5048fa2010-10-20 21:38:29 +02001455
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001456 switch (client_data.state) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001457 case INIT_SELECTING:
Felix Fietkau1c7a58d2012-09-27 16:22:24 +02001458 if (!discover_retries || packet_num < discover_retries) {
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001459 if (packet_num == 0) {
1460 change_listen_mode(LISTEN_RAW);
Mike Frysinger7031f622006-05-08 03:20:50 +00001461 xid = random_xid();
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001462 }
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001463 /* broadcast */
1464 send_discover(xid, requested_ip);
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001465 timeout = discover_timeout;
Mike Frysinger7031f622006-05-08 03:20:50 +00001466 packet_num++;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001467 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001468 }
Denis Vlasenkocdb0b652008-09-26 09:34:15 +00001469 leasefail:
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001470 change_listen_mode(LISTEN_NONE);
Denys Vlasenkof6def872021-06-03 16:14:04 +02001471 d4_run_script(NULL, "leasefail");
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001472#if BB_MMU /* -b is not supported on NOMMU */
1473 if (opt & OPT_b) { /* background if no lease */
James Byrne69374872019-07-02 11:35:03 +02001474 bb_simple_info_msg("no lease, forking to background");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001475 client_background();
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001476 /* do not background again! */
Andrey Mazo87e21622019-02-22 16:46:19 -05001477 opt = ((opt & ~(OPT_b|OPT_n)) | OPT_f);
1478 /* ^^^ also disables -n (-b takes priority over -n):
1479 * ifup's default udhcpc options are -R -n,
1480 * and users want to be able to add -b
1481 * (in a config file) to make it background
1482 * _and not exit_.
1483 */
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001484 } else
1485#endif
1486 if (opt & OPT_n) { /* abort if no lease */
James Byrne69374872019-07-02 11:35:03 +02001487 bb_simple_info_msg("no lease, failing");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001488 retval = 1;
1489 goto ret;
1490 }
Denys Vlasenko1c725372021-06-03 09:20:45 +02001491 /* Wait before trying again */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001492 timeout = tryagain_timeout;
1493 packet_num = 0;
1494 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001495 case REQUESTING:
Denys Vlasenko86d9f602016-03-04 17:00:56 +01001496 if (packet_num < 3) {
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001497 /* send broadcast select packet */
1498 send_select(xid, server_addr, requested_ip);
Denis Vlasenko6de89942008-05-21 07:05:06 +00001499 timeout = discover_timeout;
Mike Frysinger7031f622006-05-08 03:20:50 +00001500 packet_num++;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001501 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001502 }
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001503 /* Timed out, go back to init state.
1504 * "discover...select...discover..." loops
Denis Vlasenko7d9399e2008-09-26 22:21:03 +00001505 * were seen in the wild. Treat them similarly
Denis Vlasenkocdb0b652008-09-26 09:34:15 +00001506 * to "no response to discover" case */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001507 client_data.state = INIT_SELECTING;
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001508 goto leasefail;
Mike Frysinger7031f622006-05-08 03:20:50 +00001509 case BOUND:
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001510 /* 1/2 lease passed, enter renewing state */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001511 client_data.state = RENEWING;
1512 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko1c725372021-06-03 09:20:45 +02001513 got_SIGUSR1:
James Byrne69374872019-07-02 11:35:03 +02001514 log1s("entering renew state");
Denys Vlasenko1c725372021-06-03 09:20:45 +02001515 change_listen_mode(LISTEN_KERNEL);
Mike Frysinger7031f622006-05-08 03:20:50 +00001516 /* fall right through */
Denys Vlasenko1c725372021-06-03 09:20:45 +02001517 case RENEW_REQUESTED: /* in manual (SIGUSR1) renew */
Mike Frysinger7031f622006-05-08 03:20:50 +00001518 case RENEWING:
Denys Vlasenko1c725372021-06-03 09:20:45 +02001519 if (packet_num == 0) {
1520 /* Send an unicast renew request */
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001521 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1522 * a new UDP socket for sending inside send_renew.
1523 * I hazard to guess existing listening socket
1524 * is somehow conflicting with it, but why is it
1525 * not deterministic then?! Strange.
Denys Vlasenko753a3ce2009-07-19 04:27:10 +02001526 * Anyway, it does recover by eventually failing through
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001527 * into INIT_SELECTING state.
1528 */
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +02001529 if (send_renew(xid, server_addr, requested_ip) >= 0) {
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001530 timeout = discover_timeout;
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001531 packet_num++;
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +02001532 continue;
1533 }
1534 /* else: error sending.
1535 * example: ENETUNREACH seen with server
1536 * which gave us bogus server ID 1.1.1.1
1537 * which wasn't reachable (and probably did not exist).
1538 */
Denys Vlasenko1c725372021-06-03 09:20:45 +02001539 } /* else: we had sent one packet, but got no reply */
1540 log1s("no response to renew");
1541 if (lease_remaining > 30) {
1542 /* Some lease time remains, try to renew later */
1543 change_listen_mode(LISTEN_NONE);
1544 goto BOUND_for_half_lease;
Mike Frysinger7031f622006-05-08 03:20:50 +00001545 }
Denys Vlasenko1c725372021-06-03 09:20:45 +02001546 /* Enter rebinding state */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001547 client_data.state = REBINDING;
Denys Vlasenko1c725372021-06-03 09:20:45 +02001548 log1s("entering rebinding state");
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001549 /* Switch to bcast receive */
1550 change_listen_mode(LISTEN_RAW);
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001551 packet_num = 0;
Denis Vlasenko6de89942008-05-21 07:05:06 +00001552 /* fall right through */
Mike Frysinger7031f622006-05-08 03:20:50 +00001553 case REBINDING:
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001554 /* Lease is *really* about to run out,
1555 * try to find DHCP server using broadcast */
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001556 if (lease_remaining > 0 && packet_num < 3) {
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001557 /* send a broadcast renew request */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001558 send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001559 timeout = discover_timeout;
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001560 packet_num++;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001561 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001562 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001563 /* Timed out, enter init state */
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001564 change_listen_mode(LISTEN_NONE);
James Byrne69374872019-07-02 11:35:03 +02001565 bb_simple_info_msg("lease lost, entering init state");
Denys Vlasenkof6def872021-06-03 16:14:04 +02001566 d4_run_script_deconfig();
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001567 client_data.state = INIT_SELECTING;
1568 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001569 timeout = 0;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001570 packet_num = 0;
1571 continue;
1572 /* case RELEASED: */
Mike Frysinger7031f622006-05-08 03:20:50 +00001573 }
Denys Vlasenko265fcdd2021-06-02 13:50:26 +02001574 /* RELEASED state (when we got SIGUSR2) ends up here.
1575 * (wait for SIGUSR1 to re-init, or for TERM, etc)
1576 */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001577 timeout = INT_MAX;
1578 continue; /* back to main loop */
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001579 } /* if poll timed out */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001580
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001581 /* poll() didn't timeout, something happened */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001582
1583 /* Is it a signal? */
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001584 switch (udhcp_sp_read()) {
Denys Vlasenko4248c332009-06-26 23:23:16 +02001585 case SIGUSR1:
Denys Vlasenko1c725372021-06-03 09:20:45 +02001586 if (client_data.state <= REQUESTING)
1587 /* Initial negotiations in progress, do not disturb */
1588 break;
Denys Vlasenkoecaf8e82021-06-03 16:22:35 +02001589 if (client_data.state == REBINDING)
1590 /* Do not go back from rebind to renew state */
1591 break;
Denys Vlasenko1c725372021-06-03 09:20:45 +02001592
1593 if (lease_remaining > 30) /* if renew fails, do not go back to BOUND */
1594 lease_remaining = 30;
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001595 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko1c725372021-06-03 09:20:45 +02001596 packet_num = 0;
Denys Vlasenkoe6007c42021-05-01 13:48:50 +02001597
1598 switch (client_data.state) {
Denys Vlasenkoe6007c42021-05-01 13:48:50 +02001599 case BOUND:
1600 case RENEWING:
Denys Vlasenkoecaf8e82021-06-03 16:22:35 +02001601 /* Try to renew/rebind */
Denys Vlasenkoe6007c42021-05-01 13:48:50 +02001602 client_data.state = RENEW_REQUESTED;
Denys Vlasenko1c725372021-06-03 09:20:45 +02001603 goto got_SIGUSR1;
Denys Vlasenkoe6007c42021-05-01 13:48:50 +02001604
Denys Vlasenko1c725372021-06-03 09:20:45 +02001605 case RENEW_REQUESTED:
Denys Vlasenkoecaf8e82021-06-03 16:22:35 +02001606 /* Two SIGUSR1 received, start things over */
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001607 change_listen_mode(LISTEN_NONE);
Denys Vlasenkof6def872021-06-03 16:14:04 +02001608 d4_run_script_deconfig();
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001609
1610 default:
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001611 /* case RELEASED: */
Denys Vlasenkoecaf8e82021-06-03 16:22:35 +02001612 /* Wake from SIGUSR2-induced deconfigured state */
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001613 change_listen_mode(LISTEN_NONE);
Denys Vlasenkoe6007c42021-05-01 13:48:50 +02001614 }
Denys Vlasenkoe6007c42021-05-01 13:48:50 +02001615 client_data.state = INIT_SELECTING;
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001616 /* Kill any timeouts, user wants this to hurry along */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001617 timeout = 0;
1618 continue;
1619 case SIGUSR2:
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001620 perform_release(server_addr, requested_ip);
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001621 /* ^^^ switches to LISTEN_NONE */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001622 timeout = INT_MAX;
1623 continue;
1624 case SIGTERM:
James Byrne253c4e72019-04-12 17:01:51 +00001625 bb_info_msg("received %s", "SIGTERM");
Denys Vlasenko4248c332009-06-26 23:23:16 +02001626 goto ret0;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001627 }
1628
Denis Vlasenko739e30f2008-09-26 23:45:20 +00001629 /* Is it a packet? */
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001630 if (!pfds[1].revents)
Denys Vlasenko4248c332009-06-26 23:23:16 +02001631 continue; /* no */
Mike Frysinger7031f622006-05-08 03:20:50 +00001632
Denys Vlasenko4248c332009-06-26 23:23:16 +02001633 {
1634 int len;
1635
1636 /* A packet is ready, read it */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001637 if (client_data.listen_mode == LISTEN_KERNEL)
1638 len = udhcp_recv_kernel_packet(&packet, client_data.sockfd);
Denis Vlasenkob76b9a42008-01-25 22:46:34 +00001639 else
Denys Vlasenkof6def872021-06-03 16:14:04 +02001640 len = d4_recv_raw_packet(&packet, client_data.sockfd);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001641 if (len == -1) {
1642 /* Error is severe, reopen socket */
Denys Vlasenko6f97b302017-09-29 18:17:25 +02001643 bb_error_msg("read error: "STRERROR_FMT", reopening socket" STRERROR_ERRNO);
Denis Vlasenko6de89942008-05-21 07:05:06 +00001644 sleep(discover_timeout); /* 3 seconds by default */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001645 change_listen_mode(client_data.listen_mode); /* just close and reopen */
Denis Vlasenko6de89942008-05-21 07:05:06 +00001646 }
Denis Vlasenko6de89942008-05-21 07:05:06 +00001647 if (len < 0)
1648 continue;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001649 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001650
Denys Vlasenko4248c332009-06-26 23:23:16 +02001651 if (packet.xid != xid) {
Denys Vlasenkoa4959ee2021-02-21 16:32:07 +01001652 log1("xid %x (our is %x)%s",
1653 (unsigned)packet.xid, (unsigned)xid,
1654 ", ignoring packet"
1655 );
Denys Vlasenko4248c332009-06-26 23:23:16 +02001656 continue;
1657 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001658
Denys Vlasenko4248c332009-06-26 23:23:16 +02001659 /* Ignore packets that aren't for us */
1660 if (packet.hlen != 6
Denys Vlasenko949e9622021-06-02 15:51:50 +02001661 || memcmp(packet.chaddr, client_data.client_mac, 6) != 0
Denys Vlasenko4248c332009-06-26 23:23:16 +02001662 ) {
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001663//FIXME: need to also check that last 10 bytes are zero
Denys Vlasenko4bbc3912021-06-02 19:51:52 +02001664 log1("chaddr does not match%s", ", ignoring packet");
Denys Vlasenko4248c332009-06-26 23:23:16 +02001665 continue;
1666 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001667
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001668 message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001669 if (message == NULL) {
Denys Vlasenko4bbc3912021-06-02 19:51:52 +02001670 log1("no message type option%s", ", ignoring packet");
Denys Vlasenko4248c332009-06-26 23:23:16 +02001671 continue;
1672 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001673
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001674 switch (client_data.state) {
Denys Vlasenko4248c332009-06-26 23:23:16 +02001675 case INIT_SELECTING:
Denys Vlasenko860491c2011-11-18 02:09:13 +01001676 /* Must be a DHCPOFFER */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001677 if (*message == DHCPOFFER) {
Denys Vlasenko4bbc3912021-06-02 19:51:52 +02001678 struct in_addr temp_addr;
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001679 uint8_t *temp;
1680
Denys Vlasenko2af2acf2011-10-20 14:47:41 +02001681/* What exactly is server's IP? There are several values.
1682 * Example DHCP offer captured with tchdump:
1683 *
1684 * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
1685 * BOOTP fields:
1686 * Your-IP 10.34.25.202
1687 * Server-IP 10.34.32.125 // "next server" IP
1688 * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
1689 * DHCP options:
1690 * DHCP-Message Option 53, length 1: Offer
1691 * Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
1692 * Default-Gateway Option 3, length 4: 10.34.25.254 // router
1693 *
1694 * We think that real server IP (one to use in renew/release)
1695 * is one in Server-ID option. But I am not 100% sure.
Denys Vlasenkoee320c62011-10-23 18:05:58 +02001696 * IP header's src and Gateway-IP (same in this example)
Denys Vlasenko2af2acf2011-10-20 14:47:41 +02001697 * might work too.
1698 * "Next server" and router are definitely wrong ones to use, though...
1699 */
James Byrne253c4e72019-04-12 17:01:51 +00001700/* We used to ignore packets without DHCP_SERVER_ID.
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +01001701 * I've got user reports from people who run "address-less" servers.
1702 * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
1703 * They say ISC DHCP client supports this case.
1704 */
1705 server_addr = 0;
Denys Vlasenko6d3b4bb2018-12-17 18:07:18 +01001706 temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001707 if (!temp) {
James Byrne69374872019-07-02 11:35:03 +02001708 bb_simple_info_msg("no server ID, using 0.0.0.0");
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +01001709 } else {
1710 /* it IS unaligned sometimes, don't "optimize" */
1711 move_from_unaligned32(server_addr, temp);
Mike Frysinger7031f622006-05-08 03:20:50 +00001712 }
Denys Vlasenkob3af65b2010-10-20 21:37:23 +02001713 /*xid = packet.xid; - already is */
Denys Vlasenko4bbc3912021-06-02 19:51:52 +02001714 temp_addr.s_addr = requested_ip = packet.yiaddr;
Denys Vlasenko01daecc2021-06-02 20:23:43 +02001715 log1("received offer of %s", inet_ntoa(temp_addr));
Denys Vlasenko4248c332009-06-26 23:23:16 +02001716
1717 /* enter requesting state */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001718 client_data.state = REQUESTING;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001719 timeout = 0;
1720 packet_num = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001721 }
1722 continue;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001723 case REQUESTING:
1724 case RENEWING:
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001725 case RENEW_REQUESTED:
Denys Vlasenko4248c332009-06-26 23:23:16 +02001726 case REBINDING:
1727 if (*message == DHCPACK) {
Denys Vlasenko28634922014-12-21 16:10:22 +01001728 unsigned start;
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001729 struct in_addr temp_addr;
Denys Vlasenko64483322021-02-20 18:09:54 +01001730 char server_str[sizeof("255.255.255.255")];
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001731 uint8_t *temp;
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001732
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001733 change_listen_mode(LISTEN_NONE);
1734
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001735 temp_addr.s_addr = server_addr;
1736 strcpy(server_str, inet_ntoa(temp_addr));
1737 temp_addr.s_addr = packet.yiaddr;
1738
Denys Vlasenko1c725372021-06-03 09:20:45 +02001739 lease_remaining = 60 * 60;
Denys Vlasenko6d3b4bb2018-12-17 18:07:18 +01001740 temp = udhcp_get_option32(&packet, DHCP_LEASE_TIME);
Denys Vlasenko1c725372021-06-03 09:20:45 +02001741 if (temp) {
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001742 uint32_t lease;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001743 /* it IS unaligned sometimes, don't "optimize" */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001744 move_from_unaligned32(lease, temp);
1745 lease_remaining = ntohl(lease);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001746 }
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001747 /* Log message _before_ we sanitize lease */
1748 bb_info_msg("lease of %s obtained from %s, lease time %u%s",
1749 inet_ntoa(temp_addr), server_str, (unsigned)lease_remaining,
1750 temp ? "" : " (default)"
1751 );
1752 /* paranoia: must not be too small and not prone to overflows */
1753 /* NB: 60s leases _are_ used in real world
1754 * (temporary IPs while ISP modem initializes)
Denys Vlasenkoe6007c42021-05-01 13:48:50 +02001755 * do not break this case by bumping it up.
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001756 */
1757 if (lease_remaining < 0) /* signed overflow? */
1758 lease_remaining = INT_MAX;
1759 if (lease_remaining < 30)
1760 lease_remaining = 30;
1761 requested_ip = packet.yiaddr;
Denis Vlasenko223bc972007-11-22 00:58:49 +00001762#if ENABLE_FEATURE_UDHCPC_ARPING
Denys Vlasenko4248c332009-06-26 23:23:16 +02001763 if (opt & OPT_a) {
Denis Vlasenko739e30f2008-09-26 23:45:20 +00001764/* RFC 2131 3.1 paragraph 5:
1765 * "The client receives the DHCPACK message with configuration
1766 * parameters. The client SHOULD perform a final check on the
1767 * parameters (e.g., ARP for allocated network address), and notes
1768 * the duration of the lease specified in the DHCPACK message. At this
1769 * point, the client is configured. If the client detects that the
1770 * address is already in use (e.g., through the use of ARP),
1771 * the client MUST send a DHCPDECLINE message to the server and restarts
1772 * the configuration process..." */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001773 if (!arpping(requested_ip,
Denys Vlasenko4248c332009-06-26 23:23:16 +02001774 NULL,
1775 (uint32_t) 0,
Denys Vlasenko949e9622021-06-02 15:51:50 +02001776 client_data.client_mac,
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001777 client_data.interface,
Michel Stam9f412712014-10-30 11:59:04 +01001778 arpping_ms)
Denys Vlasenko4248c332009-06-26 23:23:16 +02001779 ) {
James Byrne69374872019-07-02 11:35:03 +02001780 bb_simple_info_msg("offered address is in use "
Denys Vlasenko4248c332009-06-26 23:23:16 +02001781 "(got ARP reply), declining");
Denys Vlasenko860491c2011-11-18 02:09:13 +01001782 send_decline(/*xid,*/ server_addr, packet.yiaddr);
Denis Vlasenko223bc972007-11-22 00:58:49 +00001783
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001784 if (client_data.state != REQUESTING)
Denys Vlasenkof6def872021-06-03 16:14:04 +02001785 d4_run_script_deconfig();
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001786 client_data.state = INIT_SELECTING;
1787 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001788 requested_ip = 0;
1789 timeout = tryagain_timeout;
1790 packet_num = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001791 continue; /* back to main loop */
Denis Vlasenko223bc972007-11-22 00:58:49 +00001792 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001793 }
Denis Vlasenko223bc972007-11-22 00:58:49 +00001794#endif
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001795 /* enter bound state */
Denys Vlasenko28634922014-12-21 16:10:22 +01001796 start = monotonic_sec();
Denys Vlasenkof6def872021-06-03 16:14:04 +02001797 d4_run_script(&packet, client_data.state == REQUESTING ? "bound" : "renew");
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001798 lease_remaining -= (unsigned)monotonic_sec() - start;
1799 if (lease_remaining < 0)
1800 lease_remaining = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001801 if (opt & OPT_q) { /* quit after lease */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001802 goto ret0;
1803 }
Justin Maggardaa369e02009-08-13 01:26:17 +02001804 /* future renew failures should not exit (JM) */
1805 opt &= ~OPT_n;
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001806#if BB_MMU /* NOMMU case backgrounded earlier */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001807 if (!(opt & OPT_f)) {
1808 client_background();
1809 /* do not background again! */
1810 opt = ((opt & ~OPT_b) | OPT_f);
1811 }
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001812#endif
Denys Vlasenko1c725372021-06-03 09:20:45 +02001813 BOUND_for_half_lease:
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001814 timeout = (unsigned)lease_remaining / 2;
1815 client_data.state = BOUND;
Denys Vlasenko860491c2011-11-18 02:09:13 +01001816 /* make future renew packets use different xid */
1817 /* xid = random_xid(); ...but why bother? */
Denys Vlasenko687f41f2021-06-01 00:19:03 +02001818 packet_num = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001819 continue; /* back to main loop */
Mike Frysinger7031f622006-05-08 03:20:50 +00001820 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001821 if (*message == DHCPNAK) {
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001822 /* If network has more than one DHCP server,
1823 * "wrong" server can reply first, with a NAK.
1824 * Do not interpret it as a NAK from "our" server.
1825 */
1826 if (server_addr != 0) {
1827 uint32_t svid;
1828 uint8_t *temp;
1829
Denys Vlasenko6d3b4bb2018-12-17 18:07:18 +01001830 temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001831 if (!temp) {
1832 non_matching_svid:
Peter Korsgaardb6355e22016-08-26 18:46:34 +02001833 log1("received DHCP NAK with wrong"
James Byrne69374872019-07-02 11:35:03 +02001834 " server ID%s", ", ignoring packet");
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001835 continue;
1836 }
1837 move_from_unaligned32(svid, temp);
1838 if (svid != server_addr)
1839 goto non_matching_svid;
1840 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001841 /* return to init state */
Denys Vlasenko0ae53452021-06-02 16:49:20 +02001842 change_listen_mode(LISTEN_NONE);
James Byrne253c4e72019-04-12 17:01:51 +00001843 bb_info_msg("received %s", "DHCP NAK");
Denys Vlasenkof6def872021-06-03 16:14:04 +02001844 d4_run_script(&packet, "nak");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001845 if (client_data.state != REQUESTING)
Denys Vlasenkof6def872021-06-03 16:14:04 +02001846 d4_run_script_deconfig();
Denys Vlasenko4248c332009-06-26 23:23:16 +02001847 sleep(3); /* avoid excessive network traffic */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001848 client_data.state = INIT_SELECTING;
1849 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001850 requested_ip = 0;
Denis Vlasenkob539c842007-11-29 08:17:45 +00001851 timeout = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001852 packet_num = 0;
Mike Frysinger7031f622006-05-08 03:20:50 +00001853 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001854 continue;
1855 /* case BOUND: - ignore all packets */
1856 /* case RELEASED: - ignore all packets */
Mike Frysinger7031f622006-05-08 03:20:50 +00001857 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001858 /* back to main loop */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001859 } /* for (;;) - main loop ends */
1860
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001861 ret0:
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001862 if (opt & OPT_R) /* release on quit */
1863 perform_release(server_addr, requested_ip);
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001864 retval = 0;
1865 ret:
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001866 /*if (client_data.pidfile) - remove_pidfile has its own check */
1867 remove_pidfile(client_data.pidfile);
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001868 return retval;
Mike Frysinger7031f622006-05-08 03:20:50 +00001869}